1. Field of the Invention
The present invention relates to a semiconductor device including an oxide semiconductor and a method for manufacturing the semiconductor device.
In this specification, a semiconductor device generally means a device which can function by utilizing semiconductor characteristics, and an electrooptic device, a semiconductor circuit, and an electronic appliance are all semiconductor devices.
2. Description of the Related Art
In recent years, semiconductor devices have been developed to be used mainly for a CPU, or a memory. A CPU is an aggregation of semiconductor elements each provided with an electrode which is a connection terminal, which includes a semiconductor integrated circuit (including at least a transistor and a memory) separated from a semiconductor wafer.
A semiconductor circuit (IC chip) of a CPU or a memory is mounted on a circuit board, for example, a printed wiring board, to be used as one of components of a variety of electronic appliances.
A technique for manufacturing a transistor or the like using an oxide semiconductor film for a channel formation region and applying it to a display device has been attracting attention. Examples of such a transistor include a transistor in which zinc oxide (ZnO) is used as an oxide semiconductor film and a transistor in which InGaO3(ZnO)m is used as an oxide semiconductor film.
A technique for manufacturing transistor including an oxide semiconductor film over a light-transmitting substrate and applying it to a switching element or the like of an image display device is disclosed in Patent Documents 1 and 2.
Patent Document 3 discloses a semiconductor device in which a transistor including an oxide semiconductor is provided over a single crystal substrate.